1. Field of the Invention
The present invention relates generally to a projection lens of a rear projection television (TV), and more particularly to an improved projection lens regulator for the rear projection TV.
2. Description of the Related Art
A conventional projection lens regulator for a rear projection TV, as shown in FIG. 1, is composed of a base 1′ disposed with lenses (not shown) at its bottom side, a barrel 2′ fitted inside the base 1′, and a projection lens (not shown) mounted inside the barrel 2′. The projection lens regulator is operated to adjust the relative position between the lenses (not shown) and the barrel 2′, thereby generating clear visual images on the TV. The base 1′ includes two slope guide slots 11′ positioned symmetrically at two opposite sides of an annular wall thereof. The barrel 2′ includes two columns 21′ protruded from an outer peripheral surface thereof and corresponding to the two slope guide slots 11′ for running through the two slope guide slots 11′. Two butterfly-shaped nuts 12′ are respectively threadedly mounted on the two columns 21′. While the regulator is operated to adjust the aforementioned relative position, the nuts 12′ are screwed loosely and then the two columns 21′ are moved respectively along the two slope guide slots 11′ at the same time to drive the barrel 2′ to move axially with respect to the base 1′, such that the visual images can be adjustably formed. While the aforementioned relative position is rendered optimally, the nuts 12′ are screwed tight to fasten the base 1′ and the barrel 2′ together.
While the aforementioned regulator is operated, the barrel not only moves axially with respect to the base but also rotates with respect to the base. In addition, while the aforementioned relative position is rendered optimally, the two butterfly nuts have to be screwed tight at the same time, such that the operation is complicated and subject to randomize the focal length of the projection lens so as to further reduce the quality of the visual images. Moreover, the slope guide slots are exposed outside to get dusty easily and to uglify the regulator in appearance.